Valve

ABSTRACT

A downhole valve ( 26 ) comprises a valve body ( 32 ) defining a sealing surface ( 34 ) and a flow port ( 36 ), a valve member ( 50 ) mounted within the valve body and including a sealing arrangement ( 60 ), and a protection sleeve ( 72 ) mounted within the valve body ( 32 ). The valve member is moveable within the valve body from a closed position in which the flow port is closed and the sealing arrangement sealingly engages the sealing surface of the valve body, towards an open position in which the flow port is opened and the sealing arrangement is disengaged from the sealing surface and received within the protection sleeve.

FIELD OF THE INVENTION

The present invention relates to a valve, for example to a downhole valve such as a downhole injection valve.

BACKGROUND TO THE INVENTION

In downhole oil and gas operations it is often necessary to utilise valves for the purpose of injecting a fluid from a tubing string into a wellbore. Such injection valves may be required for operations such as water flooding, formation stimulation such as fracturing and acidizing, flow bypass, flow circulation or the like.

Many forms of injection valve are known, such as a sliding sleeve valve, which includes a sleeve arranged within a tubular section having one or more ports in a side wall thereof. In a closed position the sleeve is positioned to block the ports, and is moved to an open position to unblock the ports and permit fluid flow therethrough.

Many valve types rely on good quality sealing to minimise fluid leakage when in a closed position. However, it is often the case, such as in sleeve type valves, that seals are compromised during use, for example due to exposure to flow when the associated valve is in an open state. In some cases seal damage may prevent sufficient sealing being achieved when the associated valve is returned to a closed position.

Also, in many cases downhole valves are operable by downhole fluid pressure. In such cases it may be difficult to artificially modify the downhole pressure for another purpose, such as setting another tool, without also inadvertently activating the valve.

SUMMARY OF THE INVENTION

It should be understood that terms such as “downhole”, “uphole”, “downwardly” and “upwardly”, and similar terms as used herein are not intended to provide any limitation on specific orientation. Instead, unless otherwise specified, these terms are referred to with respect to an associated wellbore when in use. For example, “uphole” or “upwardly” are intended to imply a region or direction which is towards an entry point of a wellbore, with “downhole” or “downwardly” intended to imply a region or direction which is away from an entry point of a wellbore.

An aspect of the present invention relates to a downhole valve, comprising:

a valve body defining a sealing surface and a flow port;

a valve member mounted within the valve body and including a sealing arrangement; and

a protection sleeve mounted within the valve body,

wherein the valve member is moveable within the valve body from a closed position in which the flow port is closed and the sealing arrangement sealingly engages the sealing surface of the valve body, towards an open position in which the flow port is opened and the sealing arrangement is disengaged from the sealing surface and received within the protection sleeve.

Accordingly, in use, when the valve member is in its closed position engagement between the sealing arrangement and the sealing surface may permit the flow port to be sealed, thus preventing or at least minimising flow therethrough. Further, in use, when the valve member is moved towards its open position sealing with the valve body is removed and the sealing arrangement is received within the protection sleeve, such that the sealing arrangement may be protected, for example during flow through the opened flow port. In some embodiments such an arrangement may permit the sealing arrangement to remain effective, for example to permit a seal to be re-established with the sealing surface, for example in the event of return movement of the valve member towards its closed position.

The protection sleeve may be mounted radially between the valve member and the valve body. For example, the protection sleeve may be coaxially arranged relative to the valve member and/or the valve body.

The valve member may be axially moveable within the valve body. In some embodiments the valve member may be rotatably moveable within the valve body.

The protection sleeve may be arranged to completely receive the sealing arrangement during movement of the valve member towards its open position. In other embodiments the protection sleeve may be arranged to partially receive the sealing arrangement during movement of the valve sleeve towards its open position.

The sealing surface of the valve body and an inner surface of protection sleeve may define substantially equivalent diameters to permit the sealing arrangement to move axially from the sealing surface and into the protection sleeve. In some embodiments the inner surface of the protection sleeve may define a slightly larger diameter than the sealing surface of the valve body to minimise interference between the sealing arrangement and the protection sleeve. This may assist to further prevent damage to the sealing arrangement.

The valve member may be moveable from its open position towards its closed position, to once again close the flow port.

The protection sleeve may be moveable within the valve body, for example axially and/or rotatably moveable. The protection sleeve may be moveable from a first position in which the protection sleeve covers the flow port, and a second position in which the protection sleeve uncovers the flow port. When in the first position and covering the flow port, the protection sleeve may restrict flow through the flow port. In some embodiments the protection sleeve may sealingly cover the flow port when said protection sleeve is in its first position. However, in other embodiments the protection sleeve may not necessarily sealingly close or cover the flow port, but instead may provide a barrier or obstruction over the flow port.

The protection sleeve may be moveable from its second position towards its first position to once again cover the flow port.

The protection sleeve may be moveable between its first and second positions by the valve member during movement of said valve member between its open and closed positions. The protection sleeve may be moveable in reverse directions by corresponding movement of the valve member in reverse directions.

The protection sleeve may be moveable from its first position towards its second position during movement of the valve member towards its open position. The protection sleeve may be moveable from its second position towards its first position during movement of the valve member towards its closed position.

The valve member may be moveable relative to the protection sleeve over a first range of movement of the valve member towards its open position. For example, the protection sleeve may be fixed over the first range of movement of the valve member. The first range of movement may be sufficient to permit the sealing arrangement to be received within the protection sleeve. In some embodiments the first range of movement of the valve member may be defined between a position in which the sealing arrangement sealingly engages the sealing surface of the valve body and a position in which the sealing arrangement is received, for example fully received, within the protection sleeve.

The valve member and the protection sleeve may be moveable together over a second range of movement of the valve member towards its open position. For example, the protection sleeve and the valve member may become axially secured during movement of the valve member over the second range of movement of the valve member. The second range of movement of the valve member may be defined between a position in which the sealing arrangement is received, for example fully received, within the protection sleeve, and the open position of the valve member. In such an arrangement the open position of the valve member may be achieved concurrently with the second position of the protection sleeve.

The apparatus may comprise a first loss-motion arrangement defined or provided between the valve member and the protection sleeve. The first loss-motion arrangement may permit the valve member to move relative to the protection sleeve over the first range of movement of the valve member. The loss-motion arrangement may define an axial loss-motion arrangement.

The valve member may comprise a first load shoulder, and the protection sleeve may comprise a second load shoulder. The first and second load shoulders may define axial load shoulders. One or both of the first and second shoulders may define annular shoulders. The first and second load shoulders may be separated, for example axially separated, when the valve member is located in its closed position. The first and second load shoulders may be configured to be moved together and engage each other during movement of the valve member relative to the protection sleeve, for example during movement of the valve member over its first range of movement. Engagement of the first and second load shoulders may permit the valve member to drive the protection sleeve. For example, the first and second load shoulders may be engaged at the end of the first range of movement of the valve member, which may permit the valve member to drive the protection sleeve during movement of the valve member over its second range of movement.

The protection sleeve may be arranged to remain in its first portion until the sealing arrangement is received within the protection sleeve. In such an arrangement, the valve member may be moveable relative to the protection sleeve in a direction towards the open position of the valve sleeve until the sealing arrangement is suitably received within the protection sleeve.

The protection sleeve may be releasably secured relative to the valve body. The downhole valve may comprise a releasable connection arranged between the protection sleeve and the valve body. The releasable connection may be releasable in response to movement of the valve member towards its open position. The releasable connection may be releasable when the sealing arrangement of the valve member is received, for example fully received, within the protection sleeve. The releasable connection may be released following movement of the valve member over its first range of movement, for example at the end of the first range of movement of the valve member. Such an arrangement may assist to ensure protection of the sealing arrangement.

The releasable connection may be arranged to be released upon application of a predetermined force, for example a predetermined axial force applied between the protection sleeve and the valve body. Such a force may be applied by the valve member acting on the protection sleeve, for example via respective load shoulders. The releasable connection may comprise a frangible connection. The releasable connection may comprise a shear connection.

The releasable connection may comprise a deformable body mounted in a body recess formed in one of the protection sleeve and a valve body, and a connection recess formed in the other of the protection sleeve and the valve body. When the releasable connection is in a connected state the deformable body may be received within both the body recess and the connection recess. During release, a force applied between the protection sleeve and the valve body may deform the deformable body to become removed from the connection recess, allowing relative movement between the protection sleeve and the valve body.

The deformable body may comprise a circlip or the like.

The releasable connection may be configured to provide a connection between the protection sleeve and the valve body when said protection sleeve is located at is first position. Such an arrangement may permit the protection sleeve to remain stationary until the sealing arrangement is appropriately received within said protection sleeve during movement of the valve member towards its open position.

The releasable connection may be configured to provide a connection between the protection sleeve and the valve body when said protection sleeve is located at its second position. Such an arrangement may permit the protection sleeve to remain stationary to permit the sealing arrangement to be removed from the protection sleeve during movement of the valve member towards its closed position.

The releasable connection may be resettable. This may permit re-use or resetting of the downhole valve, for example to permit the valve to be operated to be open and closed a number of times.

The valve member may be moveable relative to the protection sleeve over a third range of movement of the valve member towards its closed position. For example, the protection sleeve may be fixed over the third range of movement of the valve member. The third range of movement may be opposite the second range of movement. The third range of movement may be sufficient to permit the sealing arrangement to be removed from the protection sleeve.

The valve member and the protection sleeve may be moveable together over a fourth range of movement of the valve member towards its closed position. The fourth range of movement may be opposite to the first range of movement. The protection sleeve and the valve member may become axially secured during movement of the valve member over the fourth range of movement of the valve member. The fourth range of movement of the valve member may be defined between a position in which the sealing arrangement is removed from the protection sleeve, and the closed position of the valve member in which the sealing arrangement engages the sealing surface of the valve body. In such an arrangement the closed position of the valve member may be achieved concurrently with the first position of the protection sleeve.

The apparatus may comprise a second loss-motion arrangement defined or provided between the valve member and the protection sleeve. The second loss-motion arrangement may permit the valve member to move relative to the protection sleeve over the third range of movement of the valve member. The loss-motion arrangement may define an axial loss-motion arrangement.

The valve member may comprise a third load shoulder, and the protection sleeve may comprise a fourth load shoulder. The second and fourth load shoulders provided on the protection sleeve may defined on a common structure such as a common annular structure.

The third and fourth load shoulders may define axial load shoulders. One or both of the third and fourth load shoulders may define annular shoulders. The third and fourth load shoulders may be separated, for example axially separated, when the valve member is located in its open position. The third and fourth load shoulders may be configured to be moved together and engage each other during movement of the valve member relative to the protection sleeve, for example during movement of the valve member over its third range of movement. Engagement of the third and fourth load shoulders may permit the valve member to drive the protection sleeve. For example, the third and fourth load shoulders may be engaged at the end of the third range of movement of the valve member, which may permit the valve member to drive the protection sleeve during movement of the valve member over its fourth range of movement.

The valve member may extend through the protection sleeve. The protection sleeve may be axially shorter than the valve member. In such an arrangement the protection sleeve may be of sufficient length to receive a desired portion, for example all of the sealing arrangement.

The valve body may define an internal flow path, wherein the fluid port, when opened, facilitates fluid communication with the internal flow path. Accordingly, when the fluid port is opened, inflow or outflow relative to the internal flow path may be permitted. Inflow into the flow path may support production from a subterranean reservoir or formation. Outflow from the flow path may support injection into a subterranean reservoir or formation.

The valve member may be moveable within the valve body by a downhole fluid property. The valve member may be moveable within the valve body by action of a force arrangement, such as by a separate actuator, spring member or the like.

The valve member may be moveable towards its open position by a downhole fluid property, such as a downhole fluid pressure, flow or the like. The downhole fluid property may comprise a property of a fluid within the valve, for example within a flow path of the valve body. The downhole fluid property may comprise a property of a fluid within a wellbore, for example externally of the valve.

The valve member may be moveable towards its open position by fluid flow thorough the valve. For example, the valve member may comprise or be associated with a flow orifice, wherein flow through said orifice generates a pressure differential. This pressure differential may be used to establish a force imbalance acting on the valve member to thus urge the valve member towards its open position.

The valve member may be moveable towards its open position by fluid pressure acting on said valve, for example by fluid pressure acting over the area of the sealing arrangement when engaged with the sealing surface of the valve body. Such an arrangement may utilise a piston actuation effect.

The valve member may be moveable towards its open position by a pressure differential acting on opposing sides of the sealing arrangement when engaged with the sealing surface of the valve member. In such an arrangement fluid pressure within the downhole valve may act on one side of the sealing arrangement, and fluid pressure within an associated wellbore may act on an opposing side of the sealing arrangement.

A pressure differential, for example a positive pressure differential between the fluid internally and externally of the valve may generate or contribute to a force imbalance on the valve member to urge said valve member towards its open position.

The valve member may be moveable towards its open position by fluid momentum acting on the valve member. The valve member may be held in its open position by fluid momentum acting on the valve member.

In some embodiments the valve member may be initially urged towards its open position by fluid pressure acting over the sealing arrangement until the sealing arrangement is disengaged from the sealing surface, and then subsequently urged towards its open position by fluid momentum acting on the valve member during flow through the flow port. Such fluid momentum may function to hold the valve member in its open position.

In some embodiments the valve member may be moveable towards its open position by a valve actuator, such as a valve piston, coiled tubing or the like.

The downhole valve may comprise a biasing arrangement for biasing the valve member in a desired direction. In some embodiments the biasing arrangement may function to bias the valve member towards its closed position. In such an arrangement the valve member may be opened against the force of the biasing arrangement.

The biasing arrangement may function to minimise or dampen oscillations or shuttling of the valve member when in an open position and during flow through the open flow port.

The biasing arrangement may comprise a spring arrangement, such as a coiled spring arrangement or the like.

The valve member may be moveable towards its closed position by action of the biasing arrangement. For example a reduction or removal of a force acting to urge the valve member towards its open position may permit the biasing arrangement to generate a required force imbalance to move the valve member towards its closed position.

The valve member may be moveable towards its closed position by a downhole fluid property, such as a downhole fluid pressure, flow or the like. The downhole fluid property may comprise a property of a fluid within the valve, for example within a flow path of the valve body. The downhole fluid property may comprise a property of a fluid within a wellbore, for example externally of the valve.

The valve member may be moveable towards its closed position by fluid pressure acting on said valve, for example by fluid pressure acting over the area of the sealing arrangement when engaged with the sealing surface of the valve body.

The valve member may be moveable towards its closed position by a pressure differential acting on opposing sides of the sealing arrangement when engaged with the sealing surface of the valve member. In such an arrangement fluid pressure within the downhole valve may act on one side of the sealing arrangement, and fluid pressure within an associated wellbore may act on an opposing side of the sealing arrangement. A pressure differential, for example a negative pressure differential between the fluid internally and externally of the valve may generate or contribute to a force imbalance on the valve member to urge said valve member towards its closed position.

In some embodiments the valve member may be initially urged towards its closed position by a biasing arrangement until the sealing arrangement is engaged with the sealing surface, and then subsequently urged towards its closed position by fluid pressure, for example a differential fluid pressure, acting over the area of the sealing arrangement.

In some embodiments the valve member may be moved towards its closed position by a valve actuator, such as a valve piston or the like.

The valve member may comprise a sleeve.

The valve member may comprise a poppet.

In some embodiments the valve body may define a valve seat, wherein the valve member engages said valve seat when said valve member is located in its closed position. The provision of such a valve seat, in combination with the sealing arrangement, may facilitate improved sealing when the valve member is in its closed position. The valve seat may comprise a sealing insert, such as a metal insert, polymer insert or the like. In some embodiments the valve seat and the valve member, when engaged, may define a metal-to-metal sealing interface.

The valve member may be mounted on an axial member, such as a spigot, located within the valve body. The axial member may be rigidly secured relative to the valve body. The valve member may be mounted on an outer surface of the axial member. A portion of the valve member may be positioned within an annulus region defined between the axial member and the valve body. In such an embodiment the valve member may be axially moveable within said annulus. In some embodiments one or more fluid ports may be provided through the valve body into the annulus region. This may assist to prevent or minimise hydraulic locking of the valve member within said annulus.

A biasing arrangement may be provided between the valve member and the axial member, for example an axial end face of the axial member.

A rotational locking structure may be provided between the valve member and the axial member. The rotational lock structure may comprise a spline arrangement, non-round inter-engaging portions or the like.

The axial member may be provided on or form part of a plug assembly secured within one end of the valve body. The plug assembly may function to close one end of the valve body.

The downhole valve may comprise a releasable connection between the valve member and the valve body. The releasable connection may initially secure the valve member in its closed position. Accordingly, in use, the releasable connection must first be released to permit the valve member to be moved towards its open position.

The releasable connection may be releasable upon application of a predetermined force, such as a predetermined axial force. Accordingly, until this predetermined force is exceeded, the valve member will remain in its closed position. In some embodiments such an arrangement may permit certain downhole operations to be carried out while the valve member is retained in its closed position. For example, in embodiments where the valve member is operable by a downhole fluid pressure, the presence of the releasable connection may permit some level of variations in fluid pressure to be achieved without also causing the valve member to open. For example, some downhole operations may require elevated pressures, or sequences of elevated pressures to be established downhole, such as for pressure testing equipment, for setting other tools, such as packers, slips or the like. Once other downhole procedures are completed, the predetermined force may be exceeded, for example by increasing downhole fluid pressure, such as fluid pressure within the downhole valve, to release the releasable connection and subsequently allow the valve member to open.

The releasable connection may comprise a frangible arrangement, such as a shearing arrangement.

The releasable connection may comprise a connection member which is secured to the valve body via one or more releasable members having a force rating, wherein the valve member acts against the connection member. Thus, when a force, such as a pressure force is applied to the valve member, this force will be transmitted to the connection member. Upon exceeding the force rating of the one or more release members the connection may be released, and the valve member then permitted to move towards its open position.

In some embodiments the connection member may comprise or define a ring member which is located within the annulus between the axial member and the valve body.

The sealing arrangement may comprise one or more seal members. The sealing arrangement may comprise a chevron type seal arrangement. The seal arrangement may comprise one or more O-rings. The seal arrangement may comprise a metal seal. The seal arrangement may comprise a non-metal seal. The seal arrangement may comprise a hybrid metal and non-metal seal.

The valve body may comprise a single flow port. Alternatively, the valve body may comprise multiple flow ports. The valve body may comprise multiple flow ports arranged circumferentially around said valve body.

In some embodiments the flow area of the flow port or ports may be substantially equal to or larger than an internal flow area of the valve body. In some embodiments the flow area of the flow port or ports may be substantially equal to an annulus area defined between the valve body an d a wall of an associated wellbore. Such arrangements may minimise any fluid pressure drop during flow, for example outward and/or inward flow, through the flow port(s).

The valve body may be defined by a unitary component. Alternatively, the valve body may be defined by multiple components connected together, for example by one or more threaded connections or the like.

The downhole valve may be configured to be secured to or within a tubing string, such as a tool string. The valve may comprise one or more connectors, such as threaded connectors for permitting connection to or within a tubing string. In some embodiments the valve may mountable on an end of a tubing string, such as on a toe of a tubing string. In other embodiments the valve may be mounted in-line with a tubing string.

In some embodiments the downhole valve may be provided in combination with a sealing arrangement for providing a downhole seal. The downhole valve and the downhole seal may be provided within a common tubing or tool string. The downhole sealing arrangement may be configured to provide a seal in an annulus provided between the tubing or tool string and a wall of a wellbore in which the string is located. The downhole sealing arrangement may be configured to isolate a region adjacent the valve, for example to provide an injection region. The downhole sealing arrangement may define a bridge plug, such as is disclosed in the applicant's co-pending international patent application publication number WO 2014/006392, the disclosure of which is incorporated herein by reference. The downhole sealing arrangement may be provided in accordance with the applicant's co-pending international patent application publication number WO 2013/079965 and/or the applicant's co-pending UK patent application no. 1405009.0, the disclosure of each being incorporated herein by reference.

The downhole valve may be provided in combination with an anchor assembly for providing an anchor within an associate wellbore. The downhole valve and the anchor assembly may be provided within a common tubing or tool string. The downhole anchor assembly may be configured to anchor or secure the tubing or tool string within an associated wellbore. The downhole anchor assembly may be provided in accordance with the applicant's co-pending international patent application publication number WO 2014/006392, the disclosure of which is incorporated herein by reference.

An aspect of the present invention relates to a downhole fluid control method which utilises the downhole valve according to any other aspect.

An aspect of the present invention relates to a downhole fluid control method, comprising:

arranging a valve within a wellbore, wherein the valve includes a valve body having a sealing surface and a flow port, a valve member mounted within the valve body and including a sealing arrangement, and a protection sleeve mounted within the valve body;

arranging the valve member in a closed position in which the flow port is closed and the sealing arrangement sealingly engages the sealing surface of the valve body; and

reconfiguring the valve member towards an open position in which the flow port is opened and the sealing arrangement is disengaged from the sealing surface and received within the protection sleeve.

An aspect of the present invention relates to a downhole system, comprising:

a tubing string;

a sealing arrangement mounted on the tubing string and being operable to move from a radially retracted position to a radially extended position to engage a wall structure of a surrounding wellbore; and

a downhole valve mounted on the tubing string, wherein the downhole valve is provided in accordance with any other aspect.

The downhole valve may be positioned downhole relative to the sealing arrangement.

The sealing arrangement may define a bridge plug, such as is disclosed in the applicant's co-pending international patent application publication number WO 2014/006392, the disclosure of which is incorporated herein by reference. The sealing arrangement may be provided in accordance with the applicant's co-pending international patent application publication number WO 2013/079965 and/or the applicant's co-pending UK patent application no. 1405009.0, the disclosure of each being incorporated herein by reference.

An aspect of the present invention relates to a downhole injection system comprising a tubing string and a downhole valve according to any other aspect coupled to the tubing string.

The downhole injection system may comprise a sealing arrangement coupled to the tubing string. The downhole injection system may comprise a bridge plug arrangement coupled to the tubing string

It should be understood that the features defined in relation to one aspect may be provided in combination with any other aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1A is a cross sectional view of a lower end of a downhole tool string which incorporates a downhole valve in accordance with an embodiment of the present invention, wherein the valve is shown in a closed position:

FIG. 1B illustrates the same tool string of FIG. 1A, with the valve shown in an open configuration; and

FIGS. 2A to 2E illustrate sequential stages of the downhole valve during opening and closing.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross sectional illustration of an end region of a downhole tool string, generally identified by reference numeral 10 in accordance with an embodiment of the present invention. The tool string 10 is shown located within a wellbore, specifically a wellbore which is lined with casing or liner tubing 12.

In the embodiment shown the tool string 10 includes a bridge plug tool 14 which includes an anchor portion 16 having a number of anchor slips 18, and a sealing portion 20 having a sealing member 22. In FIG. 1A the bridge plug tool 14 is shown in a set position, in which the slips 18 of the anchor portion 16 are extended to engage the inner surface of the casing/liner 12 to axially anchor the tool string 10, and in which the sealing member 22 of the sealing portion 20 is activated and provides a seal in the annular space 24 between the tool string 10 and casing/liner 12. The bridge plug tool 14 may be provided in accordance with the applicant's co-pending international patent application publication number WO 2014/006392, the disclosure of which is incorporated herein by reference.

The tool string 10 further comprises a downhole valve, generally designated by reference numeral 26, in accordance with an embodiment of the present invention, wherein the downhole valve 26 is mounted on the lowermost end (the downhole end or toe) of the tool string 10. As will be described in further detail below, the valve 26 in the present embodiment functions as an injection valve, and is operable to be configured from a closed state, as illustrated in FIG. 1A, to an open state, as illustrated in FIG. 1B, to permit injection of fluid from the tool string 10 and into the wellbore (in the direction of arrows 30).

Reference is now made to FIG. 2A which provides an enlarged view of the downhole valve 26 in an initial closed state, removed from the tool string 10 for clarity. The valve 26 includes an outer valve body 32 which defines an axial flow path 33 and includes an inner sealing surface or bore 34 and a plurality of circumferentially arranged flow ports 36 axially spaced from the sealing surface 34. A first or uphole side of the valve body 32 includes an interface portion 38 which facilitates connection with the tool string 10 (FIG. 1), providing a fluid connection with the tool string and the flow path 33 of the valve body 32. A second or downhole side of the valve body 32 is closed by a cone portion 40 which is secured to the valve body 32 via a sealed threaded connection 42. An axial member or spigot 44 extends from the cone portion 40 and into the valve body 32, defining an annulus 46 with the inner surface of the valve body 32. A number of ports 48 are provided through the wall of the valve body 32 to provide fluid communication with the annulus 46.

The valve 26 further comprises a valve member, in the form of a valve poppet 50 which includes a valve head portion 52 and a tubular valve stem portion 54. When the valve member 50 is in its closed position, as shown in FIG. 2A, the ports 37 are covered, thus isolating said ports 36 from the flow path 33.

The valve stem 54 is mounted on or over the spigot 44, with a spring member 56 mounted within the stem 54 to act between the valve head 52 and an axial end face of the spigot 44. The spring 56 functions to bias the valve member 50 towards its illustrated closed position. The spigot 44 and the valve stem 54 may include one or more splines or non-round cooperating profiles to rotatably lock these components together.

In the closed configuration shown in FIG. 2A, the valve head 52 engages a valve seat 58 formed on an inner surface of the valve body 32. Such engagement of the valve head 52 with the valve seat 58 may provide a degree of sealing between the valve poppet 50 and the valve body 32, isolating the flow ports 36 from the flow path 33.

The valve poppet 50 further comprises a sealing arrangement 60, such as a chevron sealing arrangement, mounted on an outer surface thereof, specifically on an outer surface of the valve stem 54. The sealing arrangement 60 is axially captivated against the valve head 52 by a threaded lock ring 62. The threaded lock ring 62 defines a downwardly facing annular load shoulder 63. When the valve is in the closed position, as illustrated in FIG. 2A, the sealing arrangement 60 sealingly engages the sealing surface 34 of the valve body 32, thus isolating the flow ports 37 from the flow path 33.

The valve 26 further includes a releasable locking assembly 64 which functions to initially secure the valve poppet 50 in the closed position illustrated in FIG. 2A. The locking assembly 64 includes a connection ring member 66 which is mounted within the annulus 46 around the spigot 44, wherein the ring member 66 is secured to the valve body 32 by a number of shear screws 68. The shear screws 68 collectively define a predetermined shear rating. An annular foot 70 is mounted on the end of the valve stem 54 and axially engages the connection ring member 66. As will be described in more detail below, the releasable locking assembly 64 may be released upon application of a force exceeding the shear rating by the valve poppet 50 acting against the connection ring member 66 via the annular foot 70. The annular foot 70 also includes or defines an upwardly facing annular load shoulder 71.

The valve 26 further comprises a protection sleeve 72 coaxially mounted around the valve poppet 50, wherein the protection sleeve 72 is illustrated in FIG. 2A in a first position in which the sleeve 72 covers the flow ports 36.

An inner surface of the protection sleeve 72 defines an inner diameter which substantially corresponds to the inner diameter of the sealing surface 34 of the valve body 32. As will be described in further detail below, when the valve poppet 50 is moved towards an open position the sealing arrangement 60 is moved from the sealing surface 34 and into the protection sleeve 72, which thus functions to provide protection to the sealing arrangement 60.

The protection sleeve 72 includes an annular lip 74 which extends radially inwardly towards the outer surface of the valve stem portion 54, wherein the annular lip 74 defines an upwardly facing axial load shoulder 76 and an opposing downwardly facing axial load shoulder 78. In the initial closed configuration illustrated in FIG. 2A, the downwardly facing load shoulder 63 of the threaded lock ring 62 is axially spaced from the upwardly facing load shoulder 76 of the annular lip 74, whereas the downwardly facing load shoulder 78 of the annular lip 74 is in close proximity, for example in abutment with the upwardly facing load shoulder 71 of the foot 70.

The protection sleeve 72 also includes a releasable connection with the valve body 32. In the present embodiment the releasable connection includes a circlip 80 which is received within aligned recesses 82, 84 formed in the outer surface of the protection sleeve 72 and an inner surface of the valve body 32, respectively. As will be described in more detail below, upon application of a predetermined axial force on the protection sleeve 72, the circlip 80 will be radially compressed and displaced form the recess 84 in the valve body 32, thus axially releasing the protection sleeve 72 from the valve body 32.

In use, the valve 26 may be configured in the initial closed configuration as illustrated in FIG. 2A, such as may be the case during running of the associated tool string 10 (FIG. 1). In some circumstances, it may be necessary to elevate the fluid pressure internally of the tool string 10, and thus within the flow path 33 of the valve body 32. Such elevated fluid pressure may be required for pressure testing purposes within the tool string 10, for tool actuation such as to initiate activation of the anchor portion 16 and/or sealing portion 20, or the like. This elevated fluid pressure may act against the valve poppet 50, for example over the area of the valve seat 58 and/or over the area of the sealing arrangement 60, thus establishing a force against the valve poppet 50 in a downward direction. However, as long as this downward force is insufficient to shear the shear screws 68 of the releasable connection 64, the valve will remain closed. Accordingly, undertaking pressure-based operations within the tool string below the equivalent shear rating of the shear screws 68 may be permitted, avoiding inadvertent early activation or opening of the valve 26.

When it is desired to operate the valve 26, fluid pressure within the tool string and flow path 33 may be elevated to establish a sufficient downward net force on the valve poppet 50 to exceed the shear rating of the shear screws 68. Once the releasable connection 64 is released, this may then free the valve poppet 50 to move axially within the valve body 32 under action of the fluid pressure.

Once the valve head 52 is lifted from the valve seat 58, fluid pressure within the flow path 33 will act on one side of the sealing arrangement 60, applying a downward force on the valve poppet 50. Also, an opposite side of the sealing arrangement 60 will be exposed to fluid pressure within the annulus 24 (FIG. 1) surrounding the valve 26, thus applying an upward force on the valve poppet 50. Furthermore, the spring 56 will also provide a relatively small upward force (in comparison to the fluid pressure forces) on the valve poppet 50. Accordingly, movement of the valve poppet 50 will be in accordance with any force imbalance. In this respect, downward movement of the valve poppet 50 should be achieved when the pressure force applied by fluid within the flow path 33 exceeds the combined pressure force of fluid within the annulus 24 (FIG. 1) and the force of the spring 56. In the present embodiment the sealing arrangement 60 provides a common sealing area on opposing sides, and as such for any net movement to be achieved the pressure within the flow path 33 must be higher than pressure within the annulus 24 (FIG. 1) by at least a magnitude equivalent or proportional to the force of the spring 56.

Accordingly, during initial downward movement of the valve poppet 50, as illustrated in FIG. 2B, which shows an intermediate open position, the sealing arrangement 60 will disengage from the sealing surface 34 of the valve body 32 and will be received within the protection sleeve 72, while compressing the spring 56. At this intermediate open stage the protection sleeve 72 remains in its first position and connected to the valve body via the circlip 80 and aligned recesses 82, 84. When the sealing arrangement 60 is fully received within the protection sleeve the downwardly facing load shoulder 63 of the lock ring 62 is engaged with the upwardly facing load shoulder 76 of the annular lip 74 of the protection sleeve 72. Also, during downward movement of the valve poppet 50 the connection ring member 66 is displaced along the annulus 46, with the ports 48 preventing hydraulic locking.

When in the intermediate open position shown in FIG. 2B, although the sealing arrangement 60 no longer provides sealing engagement with the sealing surface 34, the flow ports 36 remain substantially obstructed by the protection sleeve 72 and the valve poppet 50, such that the fluid pressure within the flow path 33 still applies an effective downward force on the poppet valve 50, and now also the protection sleeve 72 via the engaging load shoulders 63, 74. When the downward force is sufficient to release the circlip 80 from its locked position, both the valve poppet 50 and the protection sleeve 72 are permitted to be axially moved to a fully open configuration, as illustrated in FIG. 2C, compressing the spring 56 further and fully opening the flow ports 36, permitting fluid to flow along the flow path 33 and outwardly through the flow ports 36. Such outward flow may be injected into a subterranean formation for example for enhancing production, formation stimulation purposes and the like. During such flow, the fluid momentum will act on the valve poppet 50 to maintain this in an open position against the bias of the spring 56. Furthermore, the spring 56 will provide a continuous upward force, which may function to minimise valve chatter.

When in the fully open position, the seal arrangement 60 is fully protected by the protection sleeve 72, and largely isolated from the fluid exiting the flow ports 36. This may assist to maintain the integrity of the sealing arrangement 60, for example to permit resealing of the valve 26 to be achieved.

In the present embodiment, the collective flow area of the flow ports 36 is selected to be substantially equivalent to both the flow area of the flow path 33, and also of the annulus 24 (FIG. 1), thus assisting to minimise any pressure drop within the fluid.

When outflow via the flow ports 36 is no longer required, the flow rate of the fluid may be reduced to such a level that the spring 56 is permitted to move the valve poppet 50 in an upward direction, as illustrated in FIG. 2D, which shows an intermediate closed position. At this position the sealing arrangement 60 is partially received within the sealing surface 34 of the valve body 32, and the downward facing load shoulder 78 of the annular lip 74 is engaged by the upward facing load shoulder 71 of the foot 70. However, the circlip 80 now engages a stepped profile on the inner surface of the valve body 32, and as such provides a degree of resistance to axial movement of the protection sleeve 72 in the upward direction.

As the sealing arrangement 60 now partially engages the sealing surface 34 a degree of sealing is achieved, and pressure externally of the valve 26 will act over the area of the sealing arrangement and apply a force on the valve poppet 50 in an upward direction. When this upward force, in combination with the spring force, is sufficient to radially compress the circlip 80, both the valve poppet 50 and the protection sleeve 72, via the engaged load shoulders 71, 78, are permitted to be moved upwardly to a fully closed position, as illustrated in FIG. 2E. In this fully closed position the valve head portion 52 re-engages the valve seat 58, the sealing arrangement 60 provides full sealing engagement with the sealing surface 34, and the protection sleeve 72 is fully closed. In this respect, as the sealing arrangement 60 was protected by the protection sleeve 72 while the ports 36 were open, a good quality seal may be re-established. Further, when the protection sleeve 72 is fully closed, the circlip 80 is re-engaged within the recess 84 in the valve body 32, thus re-establishing the releasable connection therebetween. The valve may then be re-opened by following the same procedure as above. However, in the present embodiment the releasable connection 64 is not re-settable. However, in other embodiments a re-settable connection may be provided.

As described above, the presence of the protector sleeve provides protection to the valve poppet (or any other form of valve member), and in particular to the sealing arrangement. This protection may be achieved while the valve is both closed and opened. For example, when closed, the presence of the protector sleeve may minimise exposure of the valve member to fluid externally of the valve, and when open the protector sleeve may substantially isolate the sealing arrangement from the flow of fluid.

It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention. For example, the valve may not necessarily be positioned at one end of a tool string, and instead may be positioned intermediate opposite ends thereof. Furthermore, the valve and associate tubing string may be utilised in open hole wellbore sections. Also, a full bore injection valve is disclosed in the exemplary embodiment, which may readily accommodate high injection rates. However, in other embodiments the features of the valve may be utilised in lower flow rate applications, such as in chemical injection or the like. 

1. A downhole valve, comprising: a valve body defining a sealing surface and a flow port; a valve member mounted within the valve body and including a sealing arrangement; and a protection sleeve mounted within the valve body, wherein the valve member is moveable within the valve body from a closed position in which the flow port is closed and the sealing arrangement sealingly engages the sealing surface of the valve body, towards an open position in which the flow port is opened and the sealing arrangement is disengaged from the sealing surface and received within the protection sleeve.
 2. (canceled)
 3. The downhole valve according to claim 1 wherein the valve member is axially moveable within the valve body. 4-5. (canceled)
 6. The downhole valve according to claim 1 wherein the protection sleeve is configured to be moveable within the valve body.
 7. The downhole valve according to claim 1 wherein the protection sleeve is configured to be moveable from a first position in which the protection sleeve covers the flow port, and a second position in which the protection sleeve uncovers the flow port.
 8. The downhole valve according to claim 7 wherein the protection sleeve is configured to be moveable between its first and second positions by the valve member during movement of said valve member between its open and closed positions. 9-35. (canceled)
 36. The downhole valve according to claim 1 wherein the valve member is configured to be moveable towards its open or closed position by a pressure differential acting on opposing sides of the sealing arrangement when engaged with the sealing surface of the valve member.
 37. The downhole valve according to claim 1 wherein the downhole valve comprises a biasing arrangement for biasing the valve member in a desired direction.
 38. The downhole valve according to claim 1 wherein the valve member is configured to be moveable towards its closed position by action of a biasing arrangement. 39-40. (canceled)
 41. The downhole valve according to claim 1 wherein the valve body defines a valve seat, wherein the valve member is configured to engage said valve seat when said valve member is located in its closed position.
 42. The downhole valve according to claim 1 wherein the valve member is mounted on an axial member located within the valve body. 43-47. (canceled)
 48. The downhole valve according to claim 1 wherein the sealing arrangement comprises a chevron type seal arrangement.
 49. (canceled)
 50. The downhole valve according to claim 1 wherein the seal arrangement comprises a metal seal.
 51. (canceled)
 52. The downhole valve according to wherein the seal arrangement comprises a hybrid metal and non-metal seal. 53-56. (canceled)
 57. A downhole fluid control method, comprising: arranging a valve within a wellbore, wherein the valve includes a valve body having a sealing surface and a flow port, a valve member mounted within the valve body and including a sealing arrangement, and a protection sleeve mounted within the valve body; arranging the valve member in a closed position in which the flow port is closed and the sealing arrangement sealingly engages the sealing surface of the valve body; and reconfiguring the valve member towards an open position in which the flow port is opened and the sealing arrangement is disengaged from the sealing surface and received within the protection sleeve.
 58. A downhole system, comprising: a tubing string; a sealing arrangement mounted on the tubing string and being operable to move from a radially retracted position to a radially extended position to engage a wall structure of a surrounding wellbore; and a downhole valve according claim 1 mounted on the tubing string.
 59. A downhole system according to claim 58 wherein the downhole valve is positioned downhole relative to the sealing arrangement.
 60. A downhole system according to claim 58 wherein the sealing arrangement defines a bridge plug.
 61. A downhole injection system comprising a tubing string and a downhole valve according to claim 1 coupled to the tubing string.
 62. The downhole injection system according to claim 61 comprising a sealing arrangement coupled to the tubing string.
 63. The downhole injection system according to claim 61 comprising a bridge plug arrangement coupled to the tubing string. 